Recently PC card type adapters are used for installing memory cards, using such flash memories as SD memory cards, to a personal computer. In some cases a plurality of memory cards can be simultaneously installed in one adapter (e.g. see JP9-102019 A).
On the other hand, the capacities of memory cards are increasing, and more equipment records/reproduces large volumes of data, such as images, using these memory cards. And to meet the needs of large capacities, the use of not one memory card but a plurality of memory cards installed in a PC card, so as to be used as a large capacity memory card, has been proposed.
FIG. 13 shows an exploded perspective view of a conventional PC card where four SD memory cards are installed internally, and FIG. 14 shows a perspective view of the key sections of a PC card where four SD memory cards are mounted on a printed circuit board. This PC card is secured to the frame 1 with its cover 2 able to be snapped on, so that the PC card has a slim body. In the frame 1, the printed circuit board 3 is secured by bonding. In the printed circuit board 3, the housing of the connector 4 is positioned at the center and secured. Two SD memory cards 5 are disposed facing each other at both sides of the connector 4, that is a total of four are disposed on the printed circuit board 3. In other words, two SD memory cards 5 are disposed so that the respective long sides position adjacent to each other, and this pair of SD memory cards 5 are disposed with another pair of SD memory cards 5 facing each other, sandwiching the connectors 4.
FIG. 15 is a cross-sectional view of the connector 4, where the SD memory cards 5 are connected. In FIG. 15, the contact 8, which is a plate spring, is inserted to the slit formed on the connector 4, and is secured to the housing. These contacts 8 are formed in parallel so as to contact each terminal 5a of the SD memory card 5. Each contact 8 is connected to a control LSI, for example, which is not illustrated, on the rear face of the printed circuit board 3, via the circuit pattern, which is not illustrated, formed on the printed circuit board.
At assembly the connectors 4 are mounted first on the printed circuit board 3, then the SD memory cards 5 are inserted into the connectors 4 along the printed circuit board 3. Insertion completes when the tip of the SD memory card 5 contacts the housing of the connector 4, and in this state the terminal 5a contacts the contact 8. Although not illustrated, a positioning unit is formed on the housing of the connector 4 for controlling position by contacting the end face of the SD memory card 5, so that the SD memory card 5 does not move to the short side direction (direction perpendicular to the longitudinal direction of the PC card) when the SD memory card 5 is completely inserted into the connector 4. The card connector 9 is secured at one edge of the printed circuit board 3, and can be connected to an external device, such as a computer, via this connector 9. The printed circuit board 3, on which four SD memory cards are inserted to the connectors 4 as shown in FIG. 14, is inserted into the frame 1 as shown in FIG. 13, and the printed circuit board 3 is secured to the frame 1. As FIG. 13 shows, the cushion material 20 is secured on the rear face of the cover 2, and the cover 2, engaged to the frame 1, presses the four SD memory cards 5 from the top so as to secure them to the printed circuit board 3.
However with this conventional configuration of a PC card and SD memory cards 5, the pressing force by the cushion material 20 tends to change depending on the dispersion of component accuracy, such as warping of the cover 2, and in some cases a sufficient pressing force cannot be acquired. As a result, the SD memory cards move inside the PC card, which causes a contact failure between the contact 8 of the connector 4 and the terminal 5a of the SD memory card 5.
Also when an external force is applied to the cover 2, the SD memory card 5 is pressed via the cushion material 20, and the printed circuit board 3 is warped, and as a result, the contact state of the terminal 5a of the SD memory card 5 and the contact 8 of the connector 4 changes, causing a contact failure. In some cases an external force applied to the cover 2 deforms the contact 8.
Also the SD memory cards 5 are simply covered by the frame 1 and the cover 2, and this configuration makes it difficult to protect them from the influence of static electricity from the outside.